Shi Rui, Liao Wenjie, Ramírez Pedro J, Orozco Ivan, Mahapatra Mausumi, Kang Jindong, Hunt Adrian, Waluyo Iradwikanari, Senanayake Sanjaya D, Liu Ping, Rodriguez José A
Department of Chemistry, SUNY Stony Brook, Stony Brook, NY 11794, USA.
Facultad de Ciencias, Universidad Central de Venezuela, 1020-A, Caracas, Venezuela.
Angew Chem Int Ed Engl. 2022 Sep 26;61(39):e202208666. doi: 10.1002/anie.202208666. Epub 2022 Aug 23.
In industrial catalysis, alkali cations are frequently used to promote activity or selectivity. Scanning tunneling microscopy, ambient-pressure X-ray photoelectron spectroscopy, and density-functional calculations were used to study the structure and reactivity of potassium oxides in contact with the Au(111) surface. Three different types of oxides (K O , K O and KO with y<0.5) were observed on top of the gold substrate at 300-525 K. Initially, small aggregates of K O /K O (1-2 nm in size) were seen at the elbows of the herringbone structure. After increasing the K coverage (>0.15 ML), large islands of the oxide (20-40 nm in size) appeared. These islands contained a mixture of K O and KO (y<0.5). A key correlation was found involving the structure, oxidation state, and chemical activity of the alkali oxide. The small aggregates of potassium oxide had a very high catalytic activity for the oxidation of CO, being much more than plain promoters.
在工业催化中，碱金属阳离子常用于提高活性或选择性。利用扫描隧道显微镜、常压X射线光电子能谱和密度泛函计算研究了与Au(111)表面接触的氧化钾的结构和反应活性。在300 - 525 K温度下，在金基底表面观察到三种不同类型的氧化物（KO、KO以及y < 0.5的KO）。最初，在人字形结构的拐角处可以看到KO/KO的小聚集体（尺寸为1 - 2 nm）。增加K覆盖度（> 0.15 ML）后，出现了较大的氧化物岛（尺寸为20 - 40 nm）。这些岛包含KO和KO（y < 0.5）的混合物。发现了一个涉及碱金属氧化物的结构、氧化态和化学活性的关键相关性。氧化钾的小聚集体对CO氧化具有非常高的催化活性，远高于普通促进剂。
